Process for providing a surface with a fire-proof and/or wear resistant lining

ABSTRACT

Process to provide a surface with a fire-proof and/or wear resistant lining comprising the following steps: a) mechanically fixing anchoring means to the surface, which anchoring means are pre-coated with a coating that melts at a temperature in the range from 40 to 100° C.; b) applying a lining material onto the surface provided with the anchoring means; c) curing the lining material to obtain a solid mass; d) drying the lining, to a temperature at least sufficient to melt the coating on the anchoring means, to obtain a fire-proof and/or wear resistant lining. Anchoring means used in the process.

[0001] This invention relates to a process for providing a surface witha fire-proof and/or wear resistant lining, further referred to in thisapplication as lining. In engineering it is common practice to apply alining of a fireproof and/or wear-resistant material to a surface whichis subjected to high temperatures and/or mechanical and/or chemicalloads, such as the surfaces of vessels, vessel internals or pipe-workconnecting vessels used in, for example, the cracking of petroleumproducts.

[0002] One of the major drawbacks of the processes for applying such alining to a surface that are presently used, is the commerciallyunattractive installation time. For example, the installation time for afire-proof and/or wear resistant lining consisting of a hex mesh orfloor steel anchoring system in combination with a phosphate bondedramming mass can amount up to 75 hours/m². In addition the linings ofthis type can be sensitive to thermal shocks and are difficult torepair. Furthermore it is difficult to maintain a uniform quality.

[0003] Commercially more attractive shorter installation times can beobtained by using a lining comprising a single point anchoring system,such as for example the system described in U.S. Pat. No. 5,353,503. Aproblem of these rather large anchors is that due to the difference inthermal expansion of the anchors and the lining, tensions can occurbetween the anchors and the lining, resulting in cracks in the lining.The cracking can even occur at the relatively moderate temperaturesapplied during drying of the lining. This problem is especiallyencountered when so-called wholly or partly cement-bonded materials witha low abrasion resistance are used as a lining material.

[0004] In his article titled “Equation helps select refractory anchorsystem”, published in Oil &Gas Journal, Aug. 30, 1982, pages 122-125, M.S. Crowley describes the use of mastic tape, wax and plastic coatings tocover the ends of independent anchors before the lining material isapplied. According to this article, in service, i.e. during operation,the coating burns out and leaves a small void space around the anchor soit can expand thermally without stressing the lining. This article is,however, silent about cracking problems which occur due to the build upof stress during drying of a lining.

[0005] Because the described anchoring means are welded onto thesurface, coating can only be applied after this welding step in order toavoid any damage to the coating. This adds another step to theinstallation process, making it more complicated and more laborious,resulting in increased installation time.

[0006] The object of the invention is to provide a less laboriousprocess for providing a surface with a fire-proof and/or wear resistantlining, resulting in a commercially attractive installation time, whilepreventing the lining from cracking during drying of the lining.

[0007] This object is achieved by a process to provide a surface with afire-proof and/or wear resistant lining comprising the following steps:

[0008] a) mechanically fixing anchoring means to the surface, whichanchoring means are pre-coated with a coating that melts at atemperature in the range from 40 to 100° C.;

[0009] b) applying a lining material onto the surface provided with theanchoring means;

[0010] c) curing the lining material to obtain a solid mass;

[0011] d) drying the lining, to a temperature at least sufficient tomelt the coating on the anchoring means, to obtain a fire-proof and/orwear resistant lining.

[0012] It has been found that use of this process for providing asurface with a fire-proof and/or wear resistant lining results in a lesslaborious process with a commercially attractive installation time.

[0013] The anchoring means in step a) can have any kind of shapesuitable for the purpose of holding the lining material. Suitable shapesinclude a (partial) Y, V or U shape or the shape of a cup, optionallyprovided with openings through which the lining material can enter thecup.

[0014] The size, i.e. the height and diameter, of the anchoring meansdepends on the type of lining material used, the target thickness of thefire-proof and/or wear resistant lining and the shape of the anchoringmeans itself. Depending on these factors, the size of the anchoringmeans can vary between wide ranges. The advantages of the invention areespecially clear when the anchoring means has a large diameter, i.e. adiameter of at least 3 cm. If the anchoring means has a Y, V or U shape,the diameter is defined herein as the maximum distance between the twoextremities at the top. If the anchoring means has a cup-like shape, thediameter is defined herein as the maximum distance between two points onthe circumference of the cup. The height is measured perpendicular tothe diameter. Preferably the diameter is in the range from 3 to 15 cmand the height is in the range from 1 to 15 cm. Cup-like anchoring meanspreferably have a height in the range from 0.5 to 5 cm, more preferablyin the range from 1 to 2 cm, and preferably a diameter in the range from3 to 10 cm, more preferably in the range from 3 to 7 cm. Thewall-thickness of such a cup-like anchoring means preferably lies in therange from 0.1 to 5 mm, more preferably in the range from 0.5 to 2 mm.

[0015] An example of relatively large anchoring means is the cup-likeshaped anchoring means described in U.S. Pat. No. 5,353,503. Theanchoring means, described in U.S. Pat. No. 5,353,503, have a polygonalbase portion, a plurality of lips extending perpendicularly from thepolygonal base portion, a plurality of slotted holes extending through aportion of said lips and a threaded aperture extending through thepolygonal base portion for screwing the anchoring means onto a basepart.

[0016] An example of such cup-like shaped anchoring means is the socalled SPEED CELL (SPEED CELL is a trademark owned by Silicon). Anotherexample of cup-like anchoring means is the TACO anchors (TACO is atrademark of Plibrico).

[0017] The invention is especially advantageous when used in combinationwith such large cup-like anchoring means. Generally the cup-likeanchoring means are completely embedded within the lining material.Because the cup-like anchoring means are completely embedded, stress,due to the difference in thermal expansion between the cup-likeanchoring means and the lining material, is not or hardly absorbed bythe surroundings of the anchoring means. If no measures are taken, thedifference in thermal expansion between the cup-like anchoring means andthe lining material therefore results in cracking of the lining. Coatingthe cup-like anchoring means according to this invention-prevents thelining from cracking.

[0018] The anchoring means can be manufactured from any materialsuitable to withstand the high temperatures during drying and/or firingand operation of an object wherein the fire-proof and/or wear resistantlining has been applied. Preferably the anchoring means is manufacturedfrom a metal or alloy. Preferably the anchoring means is manufacturedfrom, preferably austenitic, stainless steel.

[0019] The anchoring means are pre-coated before installation, thusbefore attachment to the surface or for example on to a base part whichis already attached to the surface. Suitably the coating melts at atemperature in the range from 40 to 100° C., preferably in the rangefrom 60 to 90° C., and more preferably in the range from 60 to 70° C.During drying of the lining in step d), the coating melts and leaves asmall void space between the anchor and the solid lining material. Thecoating can be any coating known to one skilled in the art to meltduring drying step d) as described herein. It is believed that themelted material will be absorbed by the porous lining surrounding theanchor. Preferably the coating is a wax. More preferably the coating isa microcrystalline wax, since coatings of such microcrystalline waxesare less brittle and adhere better to the anchoring means than normalwaxes. This is advantageous when the pre-coated anchors are to betransported. The melting point of the microcrystalline wax can varywithin the wide range mentioned hereabove. Examples of suitablemicrocrystalline waxes include Shell LMP, MMP and HMP waxes. Mostpreferred are microcrystalline waxes with a low melting point, i.e. amelting point in the range from 60 to 70° C. The microcrystalline waxeswith a low melting point are again less brittle and adhere better to theanchoring means than microcrystalline waxes with a high melting point.An example of a microcrystalline wax with a low melting point is theShell LMP wax, having a melting point in the range from 62 to 66° C.

[0020] The, preferably microcrystalline, wax has a hardness, asdetermined by the ASTM D1321 Test Method for Needle Penetration at 43°C. (PEN_(43° C.)) of from 70 to 160 dmm (1 dmm=0.1 mm). Wax coatingshaving a hardness within this range are more flexible which isadvantageous during transport.

[0021] The coating can be applied to the surface of the anchoring meansin any way known to one skilled in the art. When the coating is a wax,the wax is advantageously applied to the anchoring means by dipping intoor spraying with molten wax. Most preferably the wax is applied to theanchoring means by dipping into molten wax.

[0022] The coating preferably has a thickness in the range of from 0.01to 2 mm, more preferably in the range from 0.1 to 0.5 mm. The coating ispreferably applied to the whole of the anchoring means.

[0023] The pre-coated anchoring means in step a) is fixed, directly orindirectly via other (base) part(s) to the surface. Preferably theanchoring means is fixed to the surface via a base part, such as forexample a pin or stud. The anchoring means is fixed by using amechanical technique such as screwing or clicking. If the anchoringmeans is fixed indirectly via a base part the anchoring means ispreferably screwed upon such a base part.

[0024] The pre-coated anchoring means is fixed to the other (base)part(s) or the surface in a mechanical way such that the coating remainsessentially intact. By remaining essentially intact is meant thatpreferably 75% or more of the coating remains intact, more preferably90% or more remains intact and even more preferably 99% or more of thecoating remains intact during the attachment of the anchoring means tothe other (base) part(s)or the surface.

[0025] If present, the base part generally has the shape of a pin orstud. For the purpose of the invention it can, however, also be morethan one pin or a small plate or a spring or other means which can beattached to the surface and to which the anchoring means can beattached. The size, i.e. the height and diameter, of the base partdepends on the type of lining material used and the target thickness ofthe fire-proof and/or wear resistant lining. The height of the basepart, defined as the distance the base part stands out from the surface,depends mainly on the target thickness of the final fire-proof and/orwear resistant lining. For practical purposes the height of the basepart suitably lies in the range from 0.1 to 10 cm, more suitably in therange from 0.5 to 5 cm. The diameter of the base part can vary betweenwide ranges. For practical reasons the base part suitably has a diameterranging from 0.2 to 2 cm, more preferably from.0.2 to 1 cm. The basepart can be manufactured from any material suitable to withstand thehigh temperatures during drying and/or firing and operation of an objectwherein the fire-proof and/or wear resistant lining has been applied.Suitable materials include metals and metal alloys. Preferably the basepart is manufactured from a metal or alloy. More preferably the basepart is manufactured from, preferably austenitic, stainless steel.

[0026] The optional base part of the anchoring means is fixed, directlyor indirectly via extra parts, to the surface to be lined on one sideand to the anchoring means on the other side. If the base part ismanufactured from metal or metal alloy it is preferably welded to thesurface in step a). If appropriate, the base part can also be attachedto the surface by other means than welding, such as for example bymechanical ways, such as screwing or clicking. The base part can becoated or non-coated. If the base part is manufactured from a metal oralloy and is welded onto the surface, the base part is preferablynon-coated.

[0027] Preferably the anchoring means is attached to the surface asfollows:

[0028] i) welding a base part, having a threaded end remote from thesurface, to the surface.

[0029] ii) screwing anchoring means, on the base part.

[0030] The lining material in step b) can be any material known in theart to be suitable for this purpose. Suitably the lining material is amonolithic refractory material. Suitable examples include traditionalphosphate bonded materials, such as Resco AA22 (a product of RescoProducts UK) and Curas 90 PF (a product of Gouda Vuurvast); cementbonded materials, including conventional castables as well as so calledfree-flow material, such as Sureflow 93 LC (a product of Resco ProductsUK); and materials with a mixed bonding system, i.e. partly cementbonded and partly phosphate bonded such as Actchem (a product ofDramicon).

[0031] The advantages of the invention are especially clear when cementbonded or partly cement bonded materials are used, which have a superiorabrasion resistance. Materials with a superior abrasion resistance areunderstood-to be materials having an abrasion loss, measured accordingto ASTM method C704, of less than 5. Preferably the abrasion loss is inthe range of 0.1-4, more preferably in the range from 1-3. Preferablythe lining material contains less than 3% phosphates.

[0032] With the process of the present invention it is possible tocombine a cement bonded or partly cement bonded lining, and especially afree flow cement bonded lining, with cup-like anchoring means,especially large cup-like anchoring means having a diameter of at least3 cm, to obtain an essentially crack free lining. The present inventiontherefore also provides a fire-proof and/or wear resistant liningcomprising a cement bonded or partly cement bonded lining material andcup-like anchoring means, wherein a small void space is present betweenthe anchoring means and the lining material.

[0033] The lining material can be fibre reinforced, preferably withmetal, more preferably with steel fibres.

[0034] The target thickness of the fire-proof and/or wear resistantlining depends on the unit wherein it is used. Factors influencing thetarget thickness are the purpose of this unit and its shape. Suitablelining thickness' are between 1.5 and 15 cm, more preferably between 1.5to 3 cm. Suitable ways to apply the lining material include moulding,hand-packing, pouring, simple casting or vibration casting, gunning andramming methods. The temperature and pressure applied during applicationof the lining material in step b) are not critical at all, except thatcoating on the anchors should not disappear during this step. Preferredprocess conditions for step b) include an atmospheric pressure and anambient temperature, suitably a temperature in the range of 0 to 40° C.

[0035] During step c) more or less fluid lining material is cured,preferably during 6 to 24 hours, to obtain a solid mass. The temperatureduring curing suitably lies in the range from 0 to 50° C., and morepreferably in the range from 0 to 40° C. The pressure applied duringdrying is not critical. For practical purposes an atmospheric pressureis preferred.

[0036] Drying step d) can be performed as known to one skilled in theart, for example such as described in “Monolithic refractories” bySubrata Banerjee, pages 54 to 56. The temperature applied is at leastsufficient to melt the coating on the anchoring means. During this stepwater will evaporate from the lining and the coating will melt. Suitabletemperatures lie in the range from 40° C. gradually increasing to 600°C. The pressure applied during drying is not critical. For practicalpurposes an atmospheric pressure is preferred.

[0037] After step d) the lining can be optionally fired at a highertemperature, suitably lying in the range from 600 to 900° C., or can beheated further to the temperature required for the process to be carriedout in an object.

[0038] The invention further provides anchoring means, coated with acoating that melts at a temperature in the range from 40 to 100° C.,which can be mechanically fixed directly or indirectly via other (base)part(s) to a surface. Preferences are as described hereinbefore.

[0039] Preferably the anchoring means is used in combination with a basepart and thus the invention also provides a kit of parts comprising:

[0040] a) a base part

[0041] b) an anchoring means as described above, which can bemechanically fixed to the base part.

[0042] The process according to the invention for applying a fire-proofand/or wear resistant lining to a surface can advantageously be usedwhen repairing or replacing an existing lining in a unit for refinery orchemical processing, or for repairing an already existing lining, whichis damaged. The use of the process according to the invention willresult in a less laborious repair process and a shorter repair time. Thedamaged existing lining can be any type of lining known to one skilledin the art and includes for example combinations of hex-mesh,floor-steel or single point anchoring systems with brick, phosphatebonded ramming mass or cement-bonded lining material.

[0043] The process according to the invention can advantageously becarried out upon all surfaces known to one skilled in the art to becoated with a fire-proof and/or wear resistant lining. Use of afire-proof and/or wear resistant lining applied to a surface accordingto this process is especially advantageous on curved or other non-planarsurfaces, where a traditional combination of hex mesh or floor steelbased systems with phosphate bonded materials requires extralabour-intensive steps of bending and reforming the anchoring system.Advantageous applications for the fire-proof and/or wear resistantlining according to this invention are for example the applications inunits for refinery and chemical processing. The fire-proof and/or wearresistant lining can be advantageously applied in reactors, regeneratorsand especially cyclones and especially in the reactors, regenerators andcyclones of a fluidized catalytic cracking process.

[0044] The invention will now be illustrated by the followingnon-limiting examples.

EXAMPLE 1

[0045] A cup-like anchoring means as described in U.S. Pat. No.5,353,503 (SPEED CELL, obtained from Silicon)was coated with a 0.3 mmthick coating by dipping in molten microcrystalline wax with a lowmelting point (LMP microcrystalline wax, obtained from SHELL, having acongealing point of 62-66° C.), with the typical values as stated intable 1. TABLE 1 specification of the microcrystalline wax. PropertyTypical Value Melting point, ° C. (ASTM D938) 64 Penetration at 43° C.,(0.1 mm) 101 (ASTM D1321) Oil content, % m (ASTM D721) <0.1

EXAMPLE 2

[0046] A transparent perspex mould was made (1 m²). The internal spacingbetween the front and the back plate of the mould was 25 mm. The speedcell anchors of Example 1 were attached to the perspex back plate of themould using brass bolts in combination with stainless steel spacer tubes(around the brass bolts). The anchoring means almost touched the frontplate. A spacing of 8-10 cm for the speed cells was used. Sureflow 93 LC(obtained from Resco Products UK) with grains of about 2 mm was pouredinto the mould.

[0047] After 24 hours curing at ambient temperature, i.e. about 20° C.,the front panel of the mould was removed and the anchors were detachedfrom the back panel. It appeared that the anchoring means werecompletely filled up with material. After drying at about 110° C., theplate was free of cracks. The plate was fired to a temperature of 815°C. during 24 hours. The test plate remained free of cracks.

COMPARATIVE EXAMPLE A

[0048] Example 2 was repeated, except that instead of the coatedanchoring means of example 1, non-coated cup-like anchoring means asdescribed in U.S. Pat. No. 5,353,503 (SPEED CELL, obtainable fromSilicon) were used. After drying at about 110° C., fine cracks wereobserved and after firing the test plate to a temperature of 815° C.during 24 hours, the test plate showed severe cracking around theanchoring means.

1. A process to provide a surface with a fire-proof and/or wearresistant lining comprising the following steps: a) mechanically fixinganchoring means to the surface, which anchoring means are pre-coatedwith a coating that melts at a temperature in the range from 40° C. to100 ° C.; b) applying a lining material onto the surface provided withthe anchoring means; c) curing the lining material to obtain a solidmass; and d) drying the lining, to a temperature at least sufficient tomelt the coating on the anchoring means, to obtain a fire-proof and/orwear resistant lining.
 2. The process of claim 1, additionallycomprising step: e) firing the lining.
 3. The process of claim 1,wherein the anchoring means are attached to the surface via a base part.4. The process of claim 3, wherein the base part is welded to thesurface and the anchoring element is screwed upon the base part.
 5. Theprocess of claim 1, wherein the anchoring means has a diameter of atleast 3 cm.
 6. The process of claim 1, wherein the anchoring means has acup-like shape.
 7. The process claim 1, wherein the anchoring means ismanufactured from stainless steel.
 8. The process of claim 1, whereinthe anchoring means is coated with a coating that melts at a temperaturein the range from 60° C. to 90° C.
 9. The process of claim 1, whereinthe coating is a microcrystalline wax, having a melting point in therange from 60° C. to 70° C.
 10. The process of claim 1, wherein thecoating is a wax having a PEN_(43° C.) value of from 70 dmm to 160 dmm.11. The process of claim 10, wherein the pre-coated anchoring means areobtained by dipping the anchoring means into molten wax.
 12. The processof claim 1, wherein the lining material in step b) is a cement bonded orpartly cement bonded lining material.
 13. The process of claim 12,wherein the cement bonded or partly cement bonded material liningmaterial has an abrasion loss, measured according to ASTM method C704,of less than
 5. 14. An anchoring means, coated with a coating that meltsat a temperature in the range from 40° C. to 100° C., which can bemechanically fixed directly or indirectly via other (base) part(s) to asurface.
 15. A kit of parts comprising: a) a base part; and b) ananchoring means pre-coated with a coating that melts at a temperature inthe range from 40° C. to 100° C., which anchoring means can bemechanically fixed to the base part.
 16. A fire-proof and/or wearresistant lining comprising a cement bonded or partly cement bondedlining material; and, cup-like anchoring means, wherein a small voidspace is present between the anchoring means and the lining material.17. (Cancelled)
 18. (Cancelled)